Generic get/set operation for types that are stored in the <see cref="HttpContext.Cache"/>

GetFromHttpCache.cs

public static T GetFromHttpCache<T>(string key, Cache items, int cacheTime, Func<T> whenKeyNotFound, CacheItemRemovedCallback onRemoveCallback = null)
{

    if (items[key] != null)
    {
        // return from cache
        return (T)items[key];
    }

    // return new item from caller and add to cache
    var item = whenKeyNotFound();

    //add to cache            
    if(onRemoveCallback == null)
    {
        items.Insert(key, item, null, DateTime.Now.AddMinutes(cacheTime), Cache.NoSlidingExpiration);
    }
    else
    {
        items.Insert(key, item, null, DateTime.Now.AddMinutes(cacheTime), Cache.NoSlidingExpiration, CacheItemPriority.Default, onRemoveCallback);
    }

    return item;
}